Studies have suggested that American Indian and Alaska Native peoples with cancer experience poorer cancer-related survival compared to non-Native persons. This observation has raised concerns that American Indians experience disparities in access to appropriate cancer treatment services. Nevertheless, understanding the cancer care process and its relation to outcomes for Native peoples with cancer has proved difficult because (1) cancer registries often misidentify Native peoples; and (2) cancer care is usually received outside of the Indian Health Service through Contract Health Service providers or in the Medicaid program. We propose to build a comprehensive resource that links tribal and Indian Health Service enrollment files to the Surveillance, Epidemiology and End Results (SEER) Western Washington Cancer Registry to correctly identify Native peoples with breast, lung, colorectal, prostate, cervical or ovarian cancer cancer. Furthermore, in order to obtain a detailed picture of cancer care and the timing of cancer care, we plan to link the updated SEER cancer registry database with records from Contract Health Service providers and the Washington State Medicaid program. Treatments that Native peoples receive will be compared to benchmark standards established by the National Cancer Institute, as reported in the Physician Data Query (PDQ) database, and to treatment patterns for the Washington State SEER region as a whole. We hypothesize that Native persons with cancer experience delays in access to cancer care, lower rates of use of recommended treatments than other persons with cancer in the region. We further hypothesize that Native persons who experience delays in access to cancer care and/or fail to receive recommended treatments will have less favorable survival than other persons who do not experience these problems. Our research plan is greatly enhanced by the close working partnership between investigators at the Fred Hutchinson Cancer Center, the University of Washington, Indian Health Service, and senior staff at the Washington State Department of Social and Health Services.